As a Positron Emission Tomography (PET) device is limited by the factors such as hardware processing performance and manufacturing costs, its axial coverage may be not relatively large, e.g., about 15 to 20 cm. When a scanning of a large scale, for example, a whole body scan of a subject, is performed in an axial field of view, the subject lying on a scanning bed may be scanned by changing the position of the bed in a step-by-step way. Then a plurality of scanned images may be reconstructed respectively. Finally the plurality of reconstructed images may be combined together to form a whole body PET image. However, because axial sensitivity of data is not consistent during step scanning, an axial signal-to-noise ratio of the PET image may have a large fluctuation and image noise of an overlapping part may be high.
Therefore, how to improve the quality of the PET reconstructed image may be a technical problem to be solved at present.
NEUSOFT MEDICAL SYSTEMS CO., LTD. (NMS), founded in 1998 with its world headquarters in China, is a leading supplier of medical equipment, medical IT solutions, and healthcare services. NMS supplies medical equipment with a wide portfolio, including CT, Magnetic Resonance Imaging (MRI), digital X-ray machine, ultrasound, Positron Emission Tomography (PET), Linear Accelerator (LINAC), and biochemistry analyser. Currently, NMS' products are exported to over 60 countries and regions around the globe, serving more than 5,000 renowned customers. NMS's latest successful developments, such as 128 Multi-Slice CT Scanner System, Superconducting MRI, LINAC, and PET products, have led China to become a global high-end medical equipment producer. As an integrated supplier with extensive experience in large medical equipment, NMS has been committed to the study of avoiding secondary potential harm caused by excessive X-ray irradiation to the subject during the CT scanning process.